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Six speed trans life expectancy

IHscout

By IHscout
in Engines & Drivetrain

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Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted

Looking back over my notes. My current modified configuration. 180 F water thermostat and bypasses transmission thermostat give me 160-165 F on 95F days on the open road at 55 mph. In town it peaks just under 180F. Right in the factory recommended range of operation. 

 

On a 95F day under the factory limits of 207F water thermostat and 190 F trans thermostat ATF ran 200-210 F at 55 mph. 215-220 F in town and 230-240 F at 70 mph. Oil temperatures at 70 mph ran 250F. Insane. 

 

RPO C7K 6,500 GVW, JD9 7,700 pound braking system. KC4 Oil cooling Z85 Increased capacity chassis system. Meaning she's built in expectation for maximum duty and as swathdiver notes....across Death Valley. The measurements don't bear that out. 

 

So, if she ran this hot empty on warm summer day while being driven 55/70 mph and in light of the previous post comments on 'design' operation and knowns about transmission fluid degradation rates vs temperature even daily driving by a fella as conservative as myself would fall under the severe service schedule. 45-50K. And I will add that my first service at 50K, the fluid was on it's way out. Good thing I don't drive 75-80 mph eh? 

 

Unless some steps are taken to control heat even most drivers unladen 'normal operations' will bring fluid temperatures to the point of hardening seals, varnish formation and eventual failure from those conditions. Seal hardening happens no matter what fluid is in the box.  

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Cpl_Punishment Senior Enthusiast

Cpl_Punishment

Posted
Posted
On 08/03/2019 at 8:52 AM, Grumpy Bear said:

Looking back over my notes. My current modified configuration. 180 F water thermostat and bypasses transmission thermostat give me 160-165 F on 95F days on the open road at 55 mph. In town it peaks just under 180F. Right in the factory recommended range of operation. 

 

On a 95F day under the factory limits of 207F water thermostat and 190 F trans thermostat ATF ran 200-210 F at 55 mph. 215-220 F in town and 230-240 F at 70 mph. Oil temperatures at 70 mph ran 250F. Insane. 

 

RPO C7K 6,500 GVW, JD9 7,700 pound braking system. KC4 Oil cooling Z85 Increased capacity chassis system. Meaning she's built in expectation for maximum duty and as swathdiver notes....across Death Valley. The measurements don't bear that out. 

 

So, if she ran this hot empty on warm summer day while being driven 55/70 mph and in light of the previous post comments on 'design' operation and knowns about transmission fluid degradation rates vs temperature even daily driving by a fella as conservative as myself would fall under the severe service schedule. 45-50K. And I will add that my first service at 50K, the fluid was on it's way out. Good thing I don't drive 75-80 mph eh? 

 

Unless some steps are taken to control heat even most drivers unladen 'normal operations' will bring fluid temperatures to the point of hardening seals, varnish formation and eventual failure from those conditions. Seal hardening happens no matter what fluid is in the box.  

What's the Z85 system and how does it differ from the Z82 that's in the NHT max trailering package? 

CombsL83 Enthusiast

CombsL83

Posted
Posted

I've driven my '16 from Ohio to Florida a few times during July/August heat and the highest temp it reached was 196F. Truck has 51,000 miles on it and I will be doing the transmission service on it in a month or two when I can work in the garage comfortably. No issues with it I just like to stay ahead on maintenance. Already did the front and rear diffs and transfer case last summer.

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
1 hour ago, Cpl_Punishment said:

What's the Z85 system and how does it differ from the Z82 that's in the NHT max trailering package? 

A quick google search gave this result for 2013 

  • Z83 – Delivers a solid, smooth ride with monotube front and twin-tube rear shocks
  • Z85 – Designed for enhanced handling and trailer towing, with monotube front and rear shocks
  • Z71 – Delivers enhanced off-road capability; features monotube front and rear shocks
  • Z60 – Designed for maximum street performance and offered with 20-inch wheels
  • NHT – Designed for maximum towing capacity; it includes monotube rear shocks, 17-inch wheels and off-road tires, and high-capacity rear springs.
  • Z82 - is the hitch platform and wiring harness. 

Got this result for 2019

NHT Max Trailering Package, includes 9.76" rear axle, (GU6) 3.42 axle ratio, enhanced cooling radiator, revised shock tuning for increased control, heavier duty rear springs, increased RGAWR and (KW5) 220-amp alternator
1 - Requires (L84) 5.3L EcoTec3 V8 engine, (Z82) Trailering Package, (G80) locking differential and 18" or 20" wheels and tires. Includes (JL1) trailer brake controller. Not available with (Z71) Z71 Off-Road Package.
2 - Requires (L84) 5.3L EcoTec3 V8 engine or (L87) 6.2L EcoTec3 V8 engine and 18" or 20" wheels and tires. Not available with (Z71) Z71 Off-Road Package.
3 - Requires 4WD model and (L87) 6.2L EcoTec3 V8 engine. Not available with (Z71) Z71 Off-Road Package or 22" wheels.

Yondu Enthusiast

Yondu

Posted
Posted

To get back to transmission temps...do they not make a lower temp t stat for the transmission?  If stock is 195, do they make a 180 or 160?

  • 4 weeks later...
Cjmooch Enthusiast

Cjmooch

Posted
Posted

Unfortunately mine went out this week @ 73,000 miles. I have a 2014 as the second owner. Of course I am 4 months out of the warranty (as the first owner bought it 12/21/2013), so I got stuck with the bill. It is 6" on 35s but still seems way too early to go out. Future tip for those who are just out of warranty like me, GM will cover some of the cost depending on loyalty to the brand. They ended up replacing the transmission with a "new" rebuilt one direct from GM. It would have been $5400 but they knocked the bill down to $3100, which is I guess a good price because I got a couple quotes from other transmission shops and it was all right around 3000-3500. They tell me chevy has a algorithm that looks at how often you service at chevy dealerships and how many GM vehicles you have owned and stuff then it spits out a number. 

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
On ‎3‎/‎14‎/‎2019 at 9:45 PM, Yondu said:

To get back to transmission temps...do they not make a lower temp t stat for the transmission?  If stock is 195, do they make a 180 or 160?

They don't but maybe you can find something here: 

http://www.improvedracing.com/

 

  • 4 weeks later...
UnlimitedMatt Enthusiast

UnlimitedMatt

Posted
Posted
On 3/8/2019 at 8:52 AM, Grumpy Bear said:

Looking back over my notes. My current modified configuration. 180 F water thermostat and bypasses transmission thermostat give me 160-165 F on 95F days on the open road at 55 mph. In town it peaks just under 180F. Right in the factory recommended range of operation. 

 

On a 95F day under the factory limits of 207F water thermostat and 190 F trans thermostat ATF ran 200-210 F at 55 mph. 215-220 F in town and 230-240 F at 70 mph. Oil temperatures at 70 mph ran 250F. Insane. 

 

RPO C7K 6,500 GVW, JD9 7,700 pound braking system. KC4 Oil cooling Z85 Increased capacity chassis system. Meaning she's built in expectation for maximum duty and as swathdiver notes....across Death Valley. The measurements don't bear that out. 

 

So, if she ran this hot empty on warm summer day while being driven 55/70 mph and in light of the previous post comments on 'design' operation and knowns about transmission fluid degradation rates vs temperature even daily driving by a fella as conservative as myself would fall under the severe service schedule. 45-50K. And I will add that my first service at 50K, the fluid was on it's way out. Good thing I don't drive 75-80 mph eh? 

 

Unless some steps are taken to control heat even most drivers unladen 'normal operations' will bring fluid temperatures to the point of hardening seals, varnish formation and eventual failure from those conditions. Seal hardening happens no matter what fluid is in the box.  

Mr Bear, When you post your temperature figures, are you using the factory gauges or are you using some other type of scanner?

 

I just finished installing the 197° thermostat.  I also deleted my transmission thermostat and installed an external transmission spin on filter.  I also modified my tune to turn on my fans at a lower temp (used JonA's tuning suggestion).

 

Using my factory gauges, my water temp is still sitting just below 210°. My factory transmission gauge clearly shows lower temps than before.

 

Since I live in Denver, I do plan on installing a 160° transmission thermostat before winter. 

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
4 hours ago, UnlimitedMatt said:

Mr Bear, When you post your temperature figures, are you using the factory gauges or are you using some other type of scanner?

 

I just finished installing the 197° thermostat.  I also deleted my transmission thermostat and installed an external transmission spin on filter.  I also modified my tune to turn on my fans at a lower temp (used JonA's tuning suggestion).

 

Using my factory gauges, my water temp is still sitting just below 210°. My factory transmission gauge clearly shows lower temps than before.

 

Since I live in Denver, I do plan on installing a 160° transmission thermostat before winter. 

Easy on the Mr. Mr. :D

 

I use a the Linear Logic Scan Gauge II to read through the OBDII port directly from the PCM. Dash gauges are a joke. Especially the water temperature and the oil pressure.  That said the trans temp in the DIC is pretty accurate as is the amp meter speed-O, Odometer and tach. Fuel gauge is good at 1/2 only. 

 

I've been running without a trans stat for over a year now and have published the data in a bubble graph in my build thread for air temp vs trans temp at 55 mph plus a temp vs speed. I live in Northern Illinois. - 35F this winter for a record low for  my zip code.

 

I don't have a real need for a trans stat given my limited winter miles however being the fuel efficiency guy I am I may add a 145 F stat to set a 'floor' and start a second line on the graph for the data just to share. I'm a data junkie. 

 

If I might, what sort of trans temps are you getting now with the delete and lower water stat trigger? 

 

Glad it worked for you. 

 

PS, I'm currently working on a gauge pack for motor oil pressure and temperature. 

UnlimitedMatt Enthusiast

UnlimitedMatt

Posted
Posted
10 hours ago, Grumpy Bear said:

Easy on the Mr. Mr. :D

 

I use a the Linear Logic Scan Gauge II to read through the OBDII port directly from the PCM. Dash gauges are a joke. Especially the water temperature and the oil pressure.  That said the trans temp in the DIC is pretty accurate as is the amp meter speed-O, Odometer and tach. Fuel gauge is good at 1/2 only. 

 

I've been running without a trans stat for over a year now and have published the data in a bubble graph in my build thread for air temp vs trans temp at 55 mph plus a temp vs speed. I live in Northern Illinois. - 35F this winter for a record low for  my zip code.

 

I don't have a real need for a trans stat given my limited winter miles however being the fuel efficiency guy I am I may add a 145 F stat to set a 'floor' and start a second line on the graph for the data just to share. I'm a data junkie. 

 

If I might, what sort of trans temps are you getting now with the delete and lower water stat trigger? 

 

Glad it worked for you. 

 

PS, I'm currently working on a gauge pack for motor oil pressure and temperature. 

Thanks for your info, I'm going to look into Linear Logic Scan Gauge II.  I have HPT but I don't see using it with a laptop as a viable option for 'quick' checks of temps on the fly.

 

I only have a couple of days of data with the new setup. These numbers are all from the same route on my 24 mile trip to work, 95% of the trip is highway (half at 70 mph, half at 60 mph). The average air temperature has been 40 degrees, the modified transmission temperature (from the dic) average is 123 degrees. 

 

Before the mods, on the same trip, it was: Average air temperature was 38.5 degrees, the transmission temperature (from the dic) average was 168.9 degrees.

 

I'm thinking that my modified trans temps are so low because on the 2018's, the transmission cooler is part of the AC condenser, and not the radiator.  So the engine temperature is not helping the transmission warm up.

 

My main reason for my mods is to help lower my temps while towing, which I will be testing this weekend.  I'm pretty sure I will have the desired outcome, but now I may need to adjust the temps (ie: 140-160 degree trans thermostat) for my daily driving. 

 

diyer2 Senior Enthusiast

diyer2

Posted
Posted

I understand how heat is the enemy of all things mechanical and electronic.

I also understand the need to tinker.

My 2012 has no trans thermostat.

My truck does have a factory trans cooler. I could put on a better/bigger after market one. I have looked at them.

So I'm going to do more trans fluid changes to combat the heat issue.

Living in the mountains with lower temps also helps IMO.

Time will tell if my way works.

 

:)

 

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
1 hour ago, UnlimitedMatt said:

I only have a couple of days of data with the new setup. These numbers are all from the same route on my 24 mile trip to work, 95% of the trip is highway (half at 70 mph, half at 60 mph). The average air temperature has been 40 degrees, the modified transmission temperature (from the dic) average is 123 degrees. 

 

Before the mods, on the same trip, it was: Average air temperature was 38.5 degrees, the transmission temperature (from the dic) average was 168.9 degrees.

Sounds about right. 

 

1SLOW1500 has been working with Circle D transmissions upgrading his 6L80E in his turbo truck. Their recommendation for this gear box is never over 180 F for longest life. Just say' n. They do it for a living under the harshest conditions. Racing and Fleet Services. And yes they use synthetic fluids. 

 

1 hour ago, diyer2 said:

I understand how heat is the enemy of all things mechanical and electronic.

I also understand the need to tinker.

My 2012 has no trans thermostat.

My truck does have a factory trans cooler. I could put on a better/bigger after market one. I have looked at them.

So I'm going to do more trans fluid changes to combat the heat issue.

Living in the mountains with lower temps also helps IMO.

Time will tell if my way works.

 

:)

 

Wish more guys got that. If you can't or don't wish to cool it....change it. :thumbs:

That said running more than 220 / 240 F continuous is hard on more than the fluid. I can't imagine yours gets over 200F. 

 

 

diyer2 Senior Enthusiast

diyer2

Posted
Posted
16 minutes ago, Grumpy Bear said:

I can't imagine yours gets over 200F. 

 

It has according to the DIC towing my boat.

This only happens in August on my way home due to the grades I pull once I leave the main road.

After I get the boat in the garage, I let the truck run with the hood open to cool the trans and motor down.

 

;)

 

UnlimitedMatt Enthusiast

UnlimitedMatt

Posted
Posted
1 hour ago, Grumpy Bear said:

Sounds about right. 

 

1SLOW1500 has been working with Circle D transmissions upgrading his 6L80E in his turbo truck. Their recommendation for this gear box is never over 180 F for longest life. Just say' n. They do it for a living under the harshest conditions. Racing and Fleet Services. And yes they use synthetic fluids. 

 

Wish more guys got that. If you can't or don't wish to cool it....change it. :thumbs:

That said running more than 220 / 240 F continuous is hard on more than the fluid. I can't imagine yours gets over 200F. 

 

 

I get the keeping under 180 part, but what is a 'safe' operating cold temperature?

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
1 hour ago, UnlimitedMatt said:

I get the keeping under 180 part, but what is a 'safe' operating cold temperature?

You go out in the morning and it's say -5 F. So is the ATF. If it were -50, so would the ATF. Trans may be a bit lazy until you get a bit of heat in her but it doesn't 'hurt' it. They all are. Around 100F fluid temp the computer is satisfied that it's warmed up so I am too.

 

My personal temp profile says I can reach 100 F at -13F. That said there are other considerations. A bit warmer yields a bit better fuel efficiency. I ran this past winter without one to gather the data no one else has generated. Now that I have and like I said earlier, before winter sets in again I'll install the Improved Racing 145 F. I have enough cooler for my circumstances to hold it under 180 F. It is a balancing act. 

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